Method of treating steel rail and the resulting rail and joint



July2, 1940. H. s. GEORGE 2,206,839

METHOD OF TREATING STEEL RAIL AND THE RESULTING RAIL AND JOINT OriginalFiled Feb. 14, 1934 \I7 7 j INVENTOR 9 7 HARRY s. GEORGE ATTORNEYPatented July 2, 1940' j PATENT OFFIE METHOD OF TREATING STEEL RAIL ANDTHE RESULTING RAIL AND JOINT Harry S. George, Massapequa, N. Y.,assignor, by

mesne assignments, to Union Carbide and Carbon Corporation, acorporation of New York Application February 14, 1934, Serial No.711,113 Renewed February 5, 1938 28 Claims.

The present invention relates to the production of an improved rail andto a rail joint that is highly resistant in service to the deformingforces or batter normally occurring at the rail joints in railroadtracks.

When trains pass over a rail, the load applied thereto through thewheels in time gradually causes a cold flow of the metal, which finallybecomes noticeable due to a perceptible lowering of the rail treadsurface at the rail ends. Metal breaks from the rail at the tread endsas a result of this cold fiow of the metal.

Rails as produced at the steel mills have their surfaces decarburized bythe treatment undergone in their formation. This is known to produce acondition in the rail tread which exaggerates the effect of the rail endbatter encountered in normal service, and shortens the active life ofthe rail before a joint reforming treatment becomes necessary. To partlyovercome this. condition, rails have been given an overall heattreatment at the mills, thus giving the rail tread, except thedecarburized and unhardenable surface layer, a higher degree of hardnessthan it ordinarily possesses. Other prior methods involve a localheating of the rail ends or tread surface thereof to a high temperaturefollowed by a more or less rapid quenching of the heated rail portionsfor hardening purposes. In all of these methods in use prior to thepresent invention, the rail end or joint in its final form hasadecar'burized tread surface of metal of different, composition andphysical charactertread surfaces even where the latter include adecarburized surface film. Nevertheless, such heat treatment applied tothe decarburized metal lacks the power to harden such: decarburizedmetal sufficiently to prevent the initial slight depressiono f .01 'to.02 inch, due to batter which fcccurs within the first week or twoofservice. It is now known that this initial battercoupled with thenatural inequality in rail level due to Y mill tolerances on railheight-While seemingly point such that heat treatment alone may notalways be adequate to prevent excessive batter (eventual rail chipping)where the usual rails having decarburized surfaces are used.

Therefore, among the more important objects of the present inventionare: to provide a novel rail and/or rail joint free or at least largelyfree from decarburized tread surfaces before the rail or the joint isused in service; to provide a heat treated rail joint or rail endhavinga tread surface of substantially the same composition and carboncontent as the body of the rail; to pro- .vide a novel manner forraising the elastic limit of the tread portion of a rail joint or railend at or near the rail ends for limiting or preventing cold flow of themetal under service conditions; and to provide a rail end of uniformcomposition, insuring that measurements of the surface hardness shall bea true indication of the hardness of the hardened zone, thusfacilitating the accurate periodic determination of the efiicacy of thehardening treatment.

. Referring now to the accompanying drawing illustrating the presentinvention:

Fig. 1 is a side elevation of a pair of rails at "a joint (theconnecting parts being omitted) showing by dotted lines the finallocation of the tread surfaces of the rails for treatment according tothe present invention; i

Fig. 2 is a view similar to that shown in Fig. .1, with the treadsurfaces of the adjacent rails at different levels before being treatedin accordance with the present invention;

Fig. 3 is a view similar to Fig. 1 illustrating a modification of theinvention for treating rail ends before the rails are positioned in atrack;

Fig. 4 is a plan view of adjacent rails at a joint to illustrate moreclearly the manner in which the tread surface areas are ground and heattreated according ,tpthe present invention; and

Fig. 5 is similarto Fig. 4 with a narrow ground portion extendinglongitudinally of the rails at their ends. l 1

In the respective figures, the rail joint includes the adjacent ends ofthe rails 1,9, the fish, plates and connecting members being omitted forconvenience in showing the changes in the rail tread effected by thepractice of the present invention.

In the form shownin Figs. 1, 2, v4 and 5, the upper tread surfaces, l3of the rails are gently bevelled or sloped downwardly as at l5 towardthe rail joint from a distance, preferably of from 1 to 2 feet or morefrom the joint. In this manner tread surface areas at the extreme endsof the rails are slightly inclined to the tread surface areas spacedfrom the ends of the rails and adjacent to-the extreme end areas. Thisis effected by grinding so applied that the end margins of the treadsurfaces of the rails forming the joint are at the same level after thegrindmg. equally applied to the'tread surfaces of the rails near thejoint, or, if required, most of it can be applied to the receiving railbased upon the direction of traflic. The subsequent heat treatment maybe applied to a portion of the rails near the joint across their entirewidth, as shown at H, in Figs. 4 and 5.

The area thus heat-treated preferably is: generally trapezoidal ortriangular in shape, as: shown in Figs. 4 and 5. By thus terminating theheattreated portion of the tread surface diagonally, the traffic willnot pass so abruptly from a heattreated tread surface area to anupbeat-treated area or vice versa.

' In the practice of the invention in accordance with a form thereofwhich is especially adapted for the treatment of rails already laid-andpar- 7 ticularly to rail joints prior to being worn due to of theexposed undecarburizedportion I5.-

addition, a thin layer 'ofdecarburized metal will the batter oftraflicthe portions of the rails adjacent the joints, and which railshave tread surfaces decarburized at the mill to a depth of about .02 to.04 inch, are surface ground to a depth sufficient to remove asubstantial portion at least of the decarburized material, andpreferably to a depth of .02 to .04 inch or more at the rail ends, bymeans of any suitable rail-grinding machine such, for example, as theportable rail grinder disclosed in Patent No. -1,937,665 of S. R, Oldhamet a1.

Although it is generally desirable to remove substantially all of thedecarburized tread surface at the rail joint, it has beenfound inpractice that frequently the removal of portions only of thedecarburized tread surface is very beneficial, and definitely adds tothe life and serviceability of the rail. In certain instances, theremoval of around .015 inch of the decarburized material at the railtread surface has produced this marked improvement. These advantages areparticularly noticeable'after the major portion of the decarburizedmaterial has been removed from the tread surfaces. A rail grindingmachine in the hands of a skilled operator readily accomplishes thisrail tread where initial riding occurs is sufficient. For instance, oncanted rail, on tangent track, the

ground strip l5 may be around one-half inch x wide and located betweenthe middle and the outer side margin of the tread, as shown in Fig. 5.

Thus, an exposed and hardened longitudinally extending area is providedon the rail tread,

the other. Tread portions consisting of thin layers of 'decar burizedmetal overlying uridecarburized metal will thus remain on opposite sidescover the tread surface of each rail between the The grinding,therefore, may be about,

A narrow strip of ground area on the part. of the rail ends at thejoint, multiplies the effect of traffic batter by transforming therolling load into successive impacts. By the provision in a rail of along-tapered, hardened tread surface free from decarburized metal, suchimpacts are eliminated.

The rail joints of the present invention are heat-treated in a suitablemanner, either before or after the grinding operation, but preferablyafterwards. Although the grinding can be done at any time, it isgenerally preferred, where new rails are being laid, to delay thegrinding of the rail joints and ends for a day or two (but not muchlonger) after the rails have been laid, so as to allow the joints towork slightly. The angle bars may then be retightened, and the jointsground, after which the rail joints are heattreated.

One very satisfactory way of heat-treating the ground rail joint is thatset out in my Patent No. 2,075,982, issued April .6, 1937, according towhich a source of high temperature heat is directed for a shortpredetermined time upon the tread surface areas of the rails adjacentthe joint. The size of the flame and the length of time that it isapplied locally on tread surface areas are so selected that theunderlying mass of rail metal remains relatively cool, thereby rapidlytransferring heat away from the tread .surface areas. being heattreatedand exerting a quenching effect. As a result, the tread surface areasare uniformly hardened naturally to a shallow depth by the combinedcooling effect of conduction to the underlying and adjacent cold and byconvection and radiation of heat from the surfaces of the rail,

The tread surface areas to be treated-preferably triangular ortrapezoidal in shape-are quickly and uniformly raised to asuitable-temperature above the critical range of the steel, for example,about 1600 F., after which the heattreated areas cool and hardennaturally in the manner indicated. The pressure of gas and the length oftime of applying a flame for heat-treating' the tread area to thedesired depth, say 4 inch, may readily be determined by trial, for agiven size of rail and size of heat-treated area. The heat treatment ispreferably such that the resultant rail tread has a hardness of about350 Brinell. Such hardened rail will develop a scleroscope hardness ofabout 55-60, after being in service for a short time.

Fig. 3 illustrates a modification of the inven- "tion particularlyadapted for the treatment of the rail ends prior to installation of therails in a track. The rail as it comes from the mill,

I having its tread surface decarburized to a depth which area is spacedfrom both longitudinal edges of the head but is closerto one of saidedges than of .02 inch or more, is heated adjacent its ends to asuitable temperature-such as a. red heat "and the head or ball 21 of therail adjacent the end is upset in a vertical direction upwardly, asshown at 23, by forces applied at the ends of the rail ball, as byhammering or pressure thereon.

rail tread at these points.

metal of the rail,

The force applied is regulated to raise this level by an amount equal tothe depth of the decarburized surface skin or layer on the rail tread,surface.

Thereafter, upon laying the rails, the rail tread surfaces 23 adjacentthe joint are lightly ground in the manner described, to remove thedecarburized layer and preferably provide a substantially level tread atthe joint, so as to practically eliminate initial rail batter. This isthen followed by a heat treatment of a portion of the rail tread, suchas that already described.

The upsetting or reshaping of the rail ends may be effected subsequentto the installation of the rails in a track as, for example, by meansadapted to elongate the rail web at the joint the required amount. Amongsuch means may be mentioned fish plates of the type described in PatentNo. 2,004,081 of L. C. Ryan; and also that type of fish plate having acurved upper railbearing surface, the mid-portion thereof at the railjoint being its highest point; and which fish plate is adapted, uponbeing tightened against the rail, to press upwardly upon the margins ofthe rail ball at the joint for the purpose indicated. This treatment maybe applied to either a cold or a hot rail.

In any event, where the rail ends are upset by any means, the grindingoperation preferably is so conducted that the rail tread surfaces at thejoint do not slope but are in exact alignment at the same level, asshown at 21 in Fig. 3. This procedure produces a hardened tread surfaceof undecarburized metal and an initially-level joint structure.

The upsetting of the rail ends by hammerin or the like eliminates thenecessity for cross grinding, so that, if desired, the only grindingdone is that required for the removal of the surface skin ordecarburized metal on the tread surface of the rails adjacent the joint.

By the practice of the present invention, it is possible to produce atthe mill a new rail'having a level or substantially level tread, or torecondition and reform in the field a rail already in service; and toprovide a level rail joint made up of such rails. The new rail isprovided with an undecarburized wearing surface or surfaces of suitablewidth extending throughout all or a selected portion or portions of itslength. The undecarburized wearing surface may include all or only aportion of the entire rail tread surface. These undecarburized surfacesmay or may not be heat-treated in whole or in part in suitable manner,such as that descr ibed, to increase the surface hardness of the rail atsuch points.

I claim:

1. A method of reducing rail batter adjacent the end of a steel railinitially having a tread surface consisting of a relatively thin layerof decarburized metal overlying undecarburized metal, such methodcomprising removing at least a portion of said layer of decarburizedrfietal from the tread surface adjacent the end of said rail to exposethe underlying undecarburized metal; and thereafter heat treating atleast a part of such exposed undecarburized surface portion to hardenthe same.

2. A method of treating the ends: of adjacent rails having layers ofdecarburized metal, which method comprises heating an end of each rail,

upsetting each of the said rail ends in a vertical I jacent their endsan amount approximately equal to the depth of the layer of decarburizedmetal, laying the rails in place to form the rail joint, lightlygrinding the rail tread surfaces adjacent the rail joint to remove thedecarburized layer and bring the tread surfaces of the rails at thejoint to the same level, and heat-treating the rail tread surfacesadjacent the joint so' as to harden the same and render them highlyresistant to wear.

3. A method of treating at a rail joint the ends of adjacent rails whichhave surface layers of decarburized metal, which method comprisesheating an end of each rail, upsetting said rail ends in a verticaldirection while hot by impact applied upon the ends of the heads of saidrails, thereby raising the level of the respective rail treads adjacenttheir ends an amount approximately equal to the depth of the layer ofdecarburized metal, laying the rails in place to form the rail joint,lightly grinding the rail tread surfaces adjacent the rail joint toremove the decarburized layer and bring the tread surfaces of the railsat the joint to the same level, and heat-treating the .rail treadsurfaces adjacent the joint so as to harden the same and render themhighly resistant to wear.

4. A method of treating at a rail joint the ends of adjacent rails whichhave surface layers of decarburized metal, which method comprisesheating an end of each rail, upsetting said rail ends in a verticaldirection while hot by pressure applied upon the ends of the head ofsaid rails,

thereby raising the level of the respective rail treads adjacent theirends an amount at least approximately equal to the depth of the layer ofdecarburized metal, laying the rails in place to form the rail joint,lightly grinding the rail tread surfaces adjacent the rail joint toremove the decarburized layer and bring the tread surfaces of the railsat the joint to the same level, and heattreating the rail tread surfacesadjacent the joint to harden the same and render them highly resistantto wear.

5. A method of treating at a rail joint the ends of adjacent rails whichhave surface layers of decarburized metal, while the rails are in placein a track, which comprises vertically elongatingsaid rail ends therebyraising the level of the respective rail tread surfaces adjacent therail ends, lightly grinding the rail tread surfaces adjacent the railjoint to remove a substantial portion at least of the decarburized layerand bring the tread rail surfaces at the joint to substantially the samelevel, and heat-treating'the rail tread surfaces adjacent the joint toharden the same and render them highly resistant to wear.

6. A method of treating at a rail joint the ends of adjacent rails whichhave surface layers of decarburized metal, which method comprisesheating an end of each rail, upsetting said rail ends in a verticaldirection by force applied upon the ends of the heads of said rails,thereby raising the level of the respective rail tread surfaces adjacenttheir ends an amount at lea-st equal to the depth of the layer ofdecarburized metal, lightly grinding the rail tread surfaces adjacentthe rail ends sufficiently to remove at least the major portion of thedecarburized layer at such point, and heat-treating the rail treadsurfaces adjacent the joint to harden the same and render them highlyresistant to wear. r

7. A method of treating the end of a rail having a. surface layer ofdecarburized metal, which comprises heating an end of the rail,upsetting the rail end in a vertical direction while hot by forceapplied to the end of said rail, thereby increasing the height of therail tread an amount T comprises heating an end of the rail, upsettingthe rail end in a vertical direction by force applied to the end of saidrail, thereby increasing the height of the rail tread an amount in theneighborhood of .02 up to .06 inch, and lightly grinding the rail treadat the end for a distance back therefrom to at least a depth of theorder of from .02 up to .06 inch, to remove the decarburized layer atthat area.

9. A method of treating the end of a rail having a surface layer ofdecarburized metal, which comprises heating an end of the rail,upsetting the rail end in a vertical direction while hot by forceapplied to the end of said rail, thereby increasing the height of therail tread an amount approximately equal to the depth of the layer ofdecarburized metal, lightly grinding the tread at the rail end for adistance of at least one foot back therefrom to remove at least themajor portion of the decarburized layer with but slight change in thelevel of the tread surface at such point, quickly applying a regulatedamount of heat locally to the rail tread adjacent the end of the rail,and then effecting natural cooling of the thus heat-treated portion ofthe rail tread surface to harden the same.

10. A method of treating the end of a rail havcreasing the height of therail tread an amount approximately equal to the depth of the layer ofdecarburizedmetal, lightly grinding the tread at the rail end for adistance of at least one foot back therefrom to remove the decarburizedlayer with but slight change in the level of the tread surface at suchpoint, rapidly heating the tread surface of the rail at the rail endabove the critical temperature range of the metal by local applicationof a regulated quantity of heat, and allowing such heated portion tocool entirely by the conduction of heat to surroundin portions of therail body and by convection and radiation to the surrounding atmosphereso as to harden said heated tread surface.

11. A method of treating at a rail joint the ends of adjacent railshaving surface layers of decarburized metal, which method comprisesheating an end of each rail, upsetting said rail ends in a verticaldirection while hot by force applied upon the ends thereof, therebyraising the level of the respective rail treads adjacent their ends anamount approximately equal to the depth of the layer of decarburizedmetal, laying the rails in place to form the rail joint, lightlygrinding the rail tread surfaces adjacent the rail joint to remove thedecarburized layer at such point and bring the trea surfaces of therails at the joint substantially t; the same level, rapidly heating aportion at east of the ground tread surface adjacent the rail ends abovethe critical temperature range of the metal by local application of aregulated quantity of heat for a preselected time, and allowing saidheated tread surfaces to cool by the natural conduction of heattherefrom to surroundingportions of the rails and by convection andradiation to the surrounding air, in the absence of a quenching liquid.

12. A method of improving a rail having at an extreme end thereof atread surface area of decarburized metal, which comprises upsetting suchrail end in a vertical direction by force applied to the end of saidrail, thereby increasing the height of said rail tread surface an amountapproximately equal to the depth of the layer of decarburized metal, andlightly grinding said rail tread surface at the extreme end of said railto remove therefrom the layer of decarburized metal.

13. A'method according to claim 6, including the step of hardening saidtread surface area at the extreme end of said rail after the layer ofdecarburized metal has been removed therefrom.

14. A method of providing an improved rail joint comprising a pairofrails each having at an extreme end thereof a tread surface area ofdecarburized metal, which comprises upsetting such rail ends in avertical direction by force applied to the ends of said rails, therebyraising the height of the respective rail tread surfaces adjacent theirends an amount approximately equalto the depths of the layers ofdecarburized metal, laying the rails in place to form a rail joint, andlightly grinding said rail tread surface areas adjacent the joint toremove the layers of decarburized metal and bring the extreme ends ofthe tread surfaces ofitle rails substantially to the same height at theJ n 15. A method according to claim 8, including the step of hardeningsaid tread surface areas at the extreme ends of said rails after thelayers of decarburized metal have been removed therefrom.

16. A method of treating a steel rail prior to its installation in trackin order to prevent battering of the ends thereof during service intrack, such rail prior to its service in track normally having a thindecarburized metal layer upon the tread surface thereof; such methodcomprising removing said decarburized layer from at least a portion ofthe tread surface adjacent each of the ends of the rail; and thereafterapplying high temperature heat to at least a part of each of thesurfaces so exposed to heat treat the same. i

17. A method of treatinga steel rail prior to its installation in trackin order to prevent battering of the ends thereof during service intrack, such rail prior to its service in track normally having a thindecarburized metal layer upon the tread surface thereof; such methodcomprising removing said decarburized layer from only a portion of thewidth of said tread surface and longitudinally of the rail adjacent eachof its 'ends only, so as to expose underlying portions of undecarburizedmetal only adjacent such ends; thereafter applying high temperature heatto such exposed portions of undecarburized metal to heat the same to atemperature above the critical range; and effecting cooling of suchexposed and heated portions at a rate sufllcient to harden the same.

18. A steel rail having a tread surface extending throughout the lengthof the head of the rail and comprising a thin layer of decarburizedmetal overlying undecarburized metal along a major portion of the treadsurface, the remainder of said tread surface adjacent the ends of therail comprising, at least in part, exposed and hardened undecarburizedportions from which the thin layer of decarburized metal has beenremoved.

19. A steel rail having adjacent each end thereof a tread surfaceportion comprising hardened undecarburized metal; said rail also havingbetween such hardened portions a tread surface portion extendinglongitudinally of said rail and comprising a thin layer of decarburizedmetal overlying undecarburized metal.

20. A steel rail having a tread surface compris- .ing a thin layer ofdecarburized metal overlying undecarburized metal over a major portionof the length of the rail, and at each end a hardened portion from whichdecarburized metal has been removed, such hardened portions extendinglongitudinally of the rail and gradually tapering back from each end ofthe rail.

21. A new steel rail having a tread surface comprising an exposedundecarburized portion adjacent each end only of the rail, at least aportion of such undecarburized portion being hardened by heat treatment.1 22. A steel rail having upon the head thereof a tread surfacecomprising an exposed and hardened undecarburized portion adjacent eachend of the rail, such hardened portions comprising areas extendinglongitudinally of the head of the rail and narrower than the width ofsaid head.

23. A steel rail having upon the head thereof a tread surface comprisingan exposed and hard tread surface, but having an end thereof heated andsubsequently upset in a vertical direction while hot by force applied tothe end of said rail, and the decarburized layer removed by grinding fora distance of at least one foot back from the end of the rail.

25. A rail for service in track, said rail normally having a surfacelayer of decarburized metal but having an end thereof heated andsubsequently upset in a vertical direction while hot by force applied tothe end of said rail sumcient to upset the end of said rail in avertical direction an amount approximately equal to the depth of thelayer of decarburized metal, and the decarburized layer removed bygrinding for a distance at least one foot back of the end of the railwith but slight change in the level of the tread surface.

26. A steel rail having upon the head thereof a tread surface comprisingan exposed and hardened undecarburized portion adjacent an end thereof,such hardened portion comprising an area extending longitudinally of thehead of the rail and spaced from both longitudinal edges of the head butcloser to-one of said edges than the other.

27. A method of treating a steel rail which comprises preparing anundecarburized tread surface strip considerably narrower than the headof said rail and spaced from both longitudinal edges of the head of saidrail, at least a longitudinal portion of said strip being hardened; thepreparation of said strip including the step of heating and cooling atleast a longitudinal 'portion of said strip to harden the same, and thestep of removing a decarburized surface layer in the form of a stripfrom the tread of said rail.

28. A method of treating a steel rail which comprises preparing anundecarburized tread surface strip considerably narrower than the headof said rail and spaced from both edges of the head of said rail butcloser to one of said edges than the other, at least a longitudinalportion of said strip being hardened; the preparation of said stripincluding the step of heating and cooling at least a longitudinalportion of said strip to harden the same, and the step of removing adecarburized surface layer'in the form of a strip from the tread of saidrail.

HARRY S. GEORGE.

